Synthesis of Air@Co@Co₇Fe₃@Fe₃O₄ composite with enhanced electromagnetic wave absorption performance

Electromagnetic pollution prevention and military stealth technology requirements for wave absorbing materials gradually increased, therefore, the research and development of absorbing materials with the merits of low reflection loss, wide effective absorption bandwidth, and lightweight is of great significance. In this work, Air@Co@Co₇Fe₃@Fe₃O₄ hollow spherical particles have been successfully synthesized via a simple chemical plating method combined with a post heat treatment. It reveals that the Air@Co@Co₇Fe₃@Fe₃O₄ particles with a loading of 50 wt % exhibits an optimum reflection loss (RL) value of −20.77 dB at 15.52 GHz and broad effective absorption bandwidth (EAB, RL ≤ −10 dB) of 4.56 GHz with a thickness of 1.4 mm. Compared to Air@Co hollow spherical particles, Air@Co@Co₇Fe₃@Fe₃O₄ particles with natural resonance and eddy current loss, as well as the interlayer interfacial polarization mechanism of the multilayer structure, exhibit superior electromagnetic wave(EMW) absorption capabilities. The Air@Co@Co₇Fe₃@Fe₃O₄ hollow spherical particles could be a new highly efficient absorbing material for electromagnetic waves.